Internal Blow Out Preventers (IBOPs) are ball valves designed to relieve pressure and prevent blow out in high pressure drilling applications. However, these blow out preventers often fail in the field due to the high velocity mud flowing down and periodic hydrostatic testing of the IBOP valve, which is often exposed to pressures up to 16,000 psi. These hydrostatic pressures apply large loads to the valves causing them to fail.
Typically, blow-out preventers have included a dual-valve configuration comprising two separate assemblies an upper and lower blow-out preventer, which each have a single blow-out preventer valve. The redundancy of two valves is required because of the very high-pressures used and the high cycle use these valves are put through as mud saver valves. Unfortunately, the seals on these valves are subject to high strain and use and are subject to frequent failure. Because a back-up valve is always required in case of failure if a single one of these valves fails either the entire unit must be replaced, or the unit must be shut-down while repairs are performed. Neither of these options is particularly appealing because of the consumption of time and money on the drill site. Unfortunately, because of size constraints in some topdrive systems inserting an additional redundant valve between the upper and lower IBOP assemblies has not been considered feasible.
Accordingly, a need exists for an improved internal blow out preventer with improved durability and redundancy.